Exhaust silencer



Feb. 27, 1934. E, DE LAGABBE 1,949,041

EXHAUST SILENCER Filed Dec. 2 6, 1929 3 Sheets-Sheet 1 -iE-cfm v 'JIEFeb. 27, 1934. l -E DE LAC-:ABBE l 1,949,041

EXHAUST SILNCER Patented Feb. 2 7, 1.934 l .i

,UNITED STATES PATE-NT OFFICE 1,949,041 `nximus'r smENcEa Edmond deLagabbe, Paris, France Application December 26, 1929, Serial No. 416,589In France December 28, 1928 1 clam. (ci. 13a-16o) The present inventionrelates to an apparatus Figure 2 is a corresponding plan view, with forpreventing the flame and for reducing the a section on the line II--IIof Figure 3. noise caused by the exhaust of internal combus- Figure 3 isa section on the line III- III oi' tion engines, especially aircraftengines. Figure 2.

5 The invention consists in circulating the ex- Figure 4 is a detailview showing the cross- 50 haust gas between closely spaced parallelplates `bracing ofv the parallel plates. whose outer surface is incontact with a cooling Figure 5 is a plan view of a modification. fluidsuch as air. This affords a reduction of the Figure 6 is a perspectiveview of another convolume of the gas, and the speed of ow is thusstruction of the' parallel plates.

10 reduced. The cooling. action is such that all Figure 7 is a sectionalview of a silencer in 65 flames are eliminated. The closely spacedplates which the parallel plates have the radial position also aid indamping the acoustic waves. on the main conduit.`

When mounted upon aircraft or vehicles, the Figure 8 is a verticalsection of a silencer placed said apparatus is preferably placed so thatits in the path of the engine exhaust pipe.

axis extends along the direction of the wind Figure 9 is thecorresponding plan view, with 70 created by the movement of the vehicle,and the section on the line IX-IX of Figure 8. the said plates areparallel to the direction of the Figure 10 is a diagrammatic plan viewof a plant air streams. installed upon an aircraft.

In an improved apparatus the exhaustgas en- In the Aconstruction shownin Figures 1, 2, and

ters a main conduit, preferably of streamline 3, the gas delivered fromthe engine to the pipe 76 form, whose axis is perpendicular to thedirection 1, proceeds into a main conduit 2 and escapes of travel. Thegas escapes into the air after havinto the air after having been formedinto dat ing been formed into flat streams between the streams in thenarrow space between plates such parallel plates. Such plates arepreferably disas 3 and 4, 5 and 6, etc.

posed in such manner that the resultant of the On the other hand, theapparatus being dis- 80 ythrust of the escaping gas upon the air will beposed along the axis indicated by and the vehicle exercised in adirection contrary to the resistance moving in the direction of thearrow 7, a strong to the forward motion of the vehicle interposed bycurrent of air flows in the spaces between the the silencer or muffler,so that the two reactions plates 4-5, 6-8, etc.

counteract and neutralize each other. The gas The main conduit 2 isspindl/e shaped. in order 85 issues in the form of thin sheets having alarge to reduce its resistance to the air. The said plates surface ofcontact with the air, and thus the air have such form that the resultantof the thrust is drawn forward by friction, so that the gas of theescaping gas upon the air is in a direction will assure the circulationof the air when the contrary to that of the resistance to the forwardaircraft is stationary, and will also further such mOtiOn 0f the Vehicleinterposed by the plates 90 circulation during flight. themselves Theapparatus may be placed in the path f The plates 3 -4 consist of asinglesheet metal the exhaust pipe by the use of a, mamrmmke member folded onitself along the line 9--10.

conduit and a main outlet conduit,and when the gas flows from oneconduit to the other itis at a small distance from each other by cross-95 pieces consisting of washers such as 11 (Figure formed mw nat streamsby the parallel plates' 3)` secured by rivets 12; Figure 2 shows thedis- In another construction, a. :nain conduit may be used whose axis isparallel to the direction tnuioglsot uclbrotss'pisthe t ash r f thewind, and the plates may be radially diss o' eas e o av o w e s o f bystamping in each plate small bosses which 100 posed about the. saidconduit' and m such n" are connected together by a rivet or bysoldering. struction the plates are still parallel to the wind. Thisarrangement is shown m Figure 4, the plates By way of example, and forthe proper under- 13 and 14 being thus connectdstanding of thedescription, the accompanying The plates 3 and 15 rejoined m'pairs by a,5o drawings shew various embodiments ef the inrow or rivets 16, thusforming an element. such 105 vention. elements are piled up and are'joined by riveting Figure 1 is a .perspective view of a silencer thebent edges such'as 17.- A suitably curved constructed in conformity tothe invention, in piece of sheet metal 18 is riveted or soldered towhich the upper part is shown in 'section on the the extreme front partof the bent ends of all line II-II of Figure 3, with parts broken away.the plates. The ends are closed by flat sheet. 110

'I'he parts 3 and 4 are held in the parallel position r .direction oi'the air streams.

metal members such as 1920. The main central conduit, into which thepipe 1 discharges, thus has its walls formed by the sheet 18 and by thebent edges 17 of all the plates; said ends are closed by the members19--20, so that the gas can only escape by flowing through the spacesbetween the plates 3--4, 5 6, etc. The gas delivery conduit might alsoopen upon one or thev ends 19H20. f

In the construction shown in Figure 5, the plates 21 are joined byclasps or soldering at the edges 22-23. The gas follows the path shownby the arrows, and it issues at the edge 2324. Since the apparatus movesin the direction oi' the arrow 7, the direction of the escaping airstreams is practically parallel to the direction of travel.

Figure 6 shows a construction analogous to Figure 3. A metal plate iscut and stamped so as to form two anges 25--26 joined by a curved part27. An element is formed by joining said plate to a like plate 28 byrivets 29 and by means of the suitably bent sheet 30, which is solderedor 'riveted to the front edge of the part 27. A certain number of suchelements are placed together, a second element 31 being shown ln thefigure, leaving between them a space 32 for .the escape of the gasbrought to the main conduit 33. At the front part, at 34, the flanges ofone element are joined to those of the next element by their bent edgeswhich are placed together and are held by soldering, by clasps, or thelike.

Figure 7 is a section on a plane perpendicular to the main conduit 35,which is parallel to the The gas escapes by passing between the closelyspaced plates 36-37 which are radially disposed at the periphery oi.'the main conduit. The said conduit may be formed by the bent edges ofthe elements 36-37, or by the curved surfaces oi the elements which arenot parallel but radial. Said plates are strongly cooled by the airflowing between the plates.

The apparatus shown in Figures 8 and 9 is adapted for use upon theexhaustpipe. The air streams follow the path shown by the arrow 38;Figure 9 shows the position of the apparatus in the wind. This devicecomprises two main conduits of suitable outline which are placedtogether; the gas enters at the conduit 39 and issues from the conduit40. When proceeding from one conduit to the other; the gas is obliged toilow between the parallel plates, which are closely spaced, such as 41and 42, following the path indicated by the arrows in Figure 8. Saidplates may consist of sheets assembled at their edges by clasps or bysoldering. The outer surface ot said plates is properly cooled by thecurrent of air iiowlng in the direction of the arrow 38.

Figure 10 shows at 5l the aircraft engine, and upon the exhaust pipe is`disposed an apparatus comprising plates 52 analogous to what is shown inFigures 8 and 9. The plates are parallel to the direction of the airstreams, with the airplane traveling in the direction of the arrow 55.

In the apparatus 52, the gases are well cooled and are formed into flatstreams, and their volurne thus diminishes. -They are then dischargedand reach, through the pipe 53, a muiller 54 analogous to what iscurrently employed upon motor vehicles. This may consist simply of achamber of sumcient size which isproperly partitioned, and it may bedisposed in the airplane body, by reason of the low temperature of thegas ilowing through it. Due to this reduced temperature, lt can be madeof a light metal such as duralumin metal or magnesium, withoutinconvenience.

As an example, good results have been obtained by' disposing on each setof six cylinders of a 12 cylinder 500 HP engine, an apparatus having thefollowing features:

Number of pairs of plates 11 Maximum diameter of plates mm-- 400 Totalwidth ot the plates mm-- 225 Diameter of the intake conduit mm-- 120Diameter of the oli'take conduit mm- 90 Volume of the chamber disposedafter each apparatus cubic decimeters-- 40 Having now particularlydescribed and ascertained the nature of my invention and in what mannerthe same is to be performed, I declare that what I claim is:

Apparatus for treating exhaust gases of internal combustion engines,comprising a first collector for the inlet of the gas, a plurality ofpairs of closely spaced parallel plates disposed perpendicularly to theaxis o1 the said collector and maintaining a constant spacing betweeneach other, the space between the plates of each pair of plates being incommunication with the said collector, a wall between the two plates o!each pair ot plates to prevent the passage of air between the saidplates, walls between the pairs of plates to prevent the passage of gasbetween the said pairs of plates, and a second collector substantiallyparallel to the said first collector for the departure of the gas, eachplate being thus traversed by two orices, one for the entrance and onefor the departure of the gas, the walls between the two plates of eachpair of plates being continuous and creating air-tight compartments.

EDMOND nr LAGABBE.

